equals / Arrays.deepequals returns false on identical arrays

Question

I'm trying to test if two arrays are identical, I printed out every values inside them and you can see that those values are the same but for some reason the equality test always returns false. I've tried using equals as well as Arrays.deepEquals but none of those two methods work.

Here's my code:

System.out.println("========");
for (int i = 0; i < row.length; i++) {
    System.out.println("----------");
    System.out.println(row[i].getAlias());
    System.out.println(row[i].getDisplay());
    System.out.println(row[i].getModify());
    System.out.println(row[i].getName());
    System.out.println(row[i].getType());
    System.out.println(row[i].getOp());
    System.out.println(row[i].getValue());
    System.out.println("----------");
}
System.out.println("========");

for (ResultContainer rc : editedResultsList) {
    System.out.println("========");
    for (int i = 0; i < rc.getResult().length; i++) {
        System.out.println("----------");
        System.out.println(rc.getResult()[i].getAlias());
        System.out.println(rc.getResult()[i].getDisplay());
        System.out.println(rc.getResult()[i].getModify());
        System.out.println(rc.getResult()[i].getName());
        System.out.println(rc.getResult()[i].getType());
        System.out.println(rc.getResult()[i].getOp());
        System.out.println(rc.getResult()[i].getValue());
        System.out.println("----------");
    }
    System.out.println("========");
    System.out.println(rc.getResult().equals(row));
    System.out.println(Arrays.deepEquals(rc.getResult(), row));
    System.out.println(rc.getResult() == row);

    if (rc.getResult().equals(row)) {
         editedResultsList.remove(rc);
    }
}

and here's the output:

========
----------
null
false
false
mep_ident
NUMBER
insert
0
----------
----------
Numéro Partenaire
true
true
mep_ptrpartident
NUMBER
insert
000
----------
----------
Numéro Produit
true
true
mep_ptrpasident
NUMBER
insert
111
----------
----------
Code Document
true
true
mep_code_doc
VARCHAR2
insert
222
----------
----------
Production ?
true
true
mep_production
VARCHAR2
insert
333
----------
========
========
----------
null
false
false
mep_ident
NUMBER
insert
0
----------
----------
Numéro Partenaire
true
true
mep_ptrpartident
NUMBER
insert
000
----------
----------
Numéro Produit
true
true
mep_ptrpasident
NUMBER
insert
111
----------
----------
Code Document
true
true
mep_code_doc
VARCHAR2
insert
222
----------
----------
Production ?
true
true
mep_production
VARCHAR2
insert
333
----------
========
false
false
false
true

morgano · Accepted Answer · 2013-08-02T08:42:59.750

2

From the Javadoc:

Two possibly null elements e1 and e2 are deeply equal if any of the following conditions hold:
- e1 and e2 are both arrays of object reference types, and Arrays.deepEquals(e1, e2) would return true
- e1 and e2 are arrays of the same primitive type, and the appropriate overloading of Arrays.equals(e1, e2) would return true.
- e1 == e2
- e1.equals(e2) would return true.

About the class of the objects you have in your arrays, make sure that overrides equals() and hashcode() properly.

UPDATE

Consult the Object javadoc, basically you need to add this to your class:

@Override
public boolean equals(Object other) {
    // Add here code to verifiy that this object is "equals"
    // to the method argument "other".
    // return true if they are equal or false otherwise
}

@Override
public int hashCode() {
    // Return here a "hash" integer (two objects equals to each other
    // must return the same hashcode)
}

edited Aug 02 '13 at 08:42

answered Aug 02 '13 at 08:24

morgano

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From the last line, shouldn't that be a comment? – tbodt Aug 02 '13 at 08:25
I have not overrided equals and hashcode at all in that class. – noisegrrrl Aug 02 '13 at 08:25
@tbodt I didn't understand your comment, but anyway I rewrote the last part. – morgano Aug 02 '13 at 08:28
@Emualynk do it and try again – morgano Aug 02 '13 at 08:32
I'm not exactly sure of what I'm supposed to do when overriding the methods though? – noisegrrrl Aug 02 '13 at 08:35
see http://stackoverflow.com/questions/27581/overriding-equals-and-hashcode-in-java?rq=1 – JohannesR Aug 02 '13 at 08:39
Thanks for the help, I've overridden the methods and deepEquals is now working. – noisegrrrl Aug 02 '13 at 08:47

score 0 · Answer 2 · 2013-08-02T08:49:16.850

Specify your two array where you have created because getAliase() and all those method are not using by primitive type data-type.I am giving here code for primitive type if I will get your actual array I will modify my code.

public class ChecktwoArray {


public static void main(String[] args) {
    int a[]={2,5,6};
    int b[]={2,5,6};
    System.out.println(Arrays.equals(a,b));

}

}

If you are using another array then you have to override these methods because without hashcode() ,toString() method will check only memory address not the content

@Override
public boolean equals(Object obj) {
    // TODO Auto-generated method stub
    return super.equals(obj);
}

@Override
public int hashCode() {
    // TODO Auto-generated method stub
    return super.hashCode();
}

@Override
public String toString() {
    // TODO Auto-generated method stub
    return super.toString();
}

[@tbodt](http://stackoverflow.com/users/1455016/tbodt) I think this will work properly. — , Aug 02 '13 at 08:51

equals / Arrays.deepequals returns false on identical arrays

2 Answers2